HOW TO CHANGE OXYGEN SENSOR
How to change an oxygen sensor on 2003 GMC Sierra 1500.
- Oxygen sensor socket
- anti seize
- Oxygen sensor
This customer has a P0420 code. This is common for a failed oxygen sensor for Bank 1 Sensor 1. Bank 1 is the driver side of the engine. Bank 2 is the passenger side of the engine. Sensor 1 is before the catalytic converter and sensor 2 is aft of the catalytic converter.
Removal: Disconnect the pig tail on the sensor. This is where the sensor connects to the wiring harness. After this is removed, use an oxygen sensor socket and a ratchet to remove the sensor. A wrench will work if it will fit. Use the box end if possible because these sensors will be hard to turn. If the sensor was installed with anti seize then it will be easier to remove.
Installation: Apply anti seize onto the threads of the sensor. Thread the sensor into the bung on the exhaust. Tighten the sensor. Reconnect the electrical connector to the wiring harness.